4m+9+5m-12=42
Combine 9 and -12 and you get -3 so
4m+5m-3=42
And then combine 4m and 5m and you get 9m so
9m-3=42
And then add three on both sides (canceling out the -3) leaving you with
9m=45
And then divide 45 by 9 and you get 5 so
m=5.
The answer is A. M=5
